Dry, cold air has settled over the Tampa Bay region, but a warming trend will drive temperatures back to normal this weekend. In preparation for the chilly night, Hillsborough County is opening its cold-weather shelters this afternoon.

A freeze warning is in effect tonight for Citrus and Hernando counties. Lighter winds in the forecast will mean a better chance for frost as well. Temperatures will down to 42 overnight, News Channel 8 meteorologist Leigh Spann said.

A gradual warming trend will begin Thursday and continue through the weekend.

Ahead of the chilly night, Hillsborough County is opening its cold-weather shelters this afternoon. The shelters are for homeless people and residents who live in homes without adequate heat. Most close the next day at 7 a.m.:

Wimauma Community Center, 5705 Hillsborough St., Wimauma, opens at 6 p.m. and is for adults and families. (813) 635-3500.

Hillsborough County, which is opening the shelters for the seventh time this season, coordinates with the shelters to open when the predicted temperature falls to 32 degrees or degrees, including wind chill. The shelters opened eight times last winter, and helped 1,599 people.

Donations to the Hillsborough cold-weather shelters can be made at these community centers: Brandon, Jackson Springs and Wimauma. The facilities accept blankets, disinfectant wipes, disposable cups, coffee, creamer, paper plates, plastic utensils and sugar.

Meals for the shelters are provided through Metropolitan Ministries, which also accepts donations of nonperishable items. Call (813) 209-1000.